﻿// 
// Copyright (c) 2004-2018 Jaroslaw Kowalski <jaak@jkowalski.net>, Kim Christensen, Julian Verdurmen
// 
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without 
// modification, are permitted provided that the following conditions 
// are met:
// 
// * Redistributions of source code must retain the above copyright notice, 
//   this list of conditions and the following disclaimer. 
// 
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution. 
// 
// * Neither the name of Jaroslaw Kowalski nor the names of its 
//   contributors may be used to endorse or promote products derived from this
//   software without specific prior written permission. 
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 
// THE POSSIBILITY OF SUCH DAMAGE.
// 

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;

namespace NLog.MessageTemplates
{
    /// <summary>
    /// Parse templates.
    /// </summary>
    internal static class TemplateParser
    {
        /// <summary>
        /// Parse a template.
        /// </summary>
        /// <param name="template">Template to be parsed.</param>
        /// <exception cref="ArgumentNullException">When <paramref name="template"/> is null.</exception>
        /// <returns>Template, never null</returns>
        public static Template Parse(string template)
        {
            if (template == null)
                throw new ArgumentNullException(nameof(template));

            bool isPositional = true;
            List<Literal> literals = new List<Literal>();
            List<Hole> holes = new List<Hole>();

            TemplateEnumerator templateEnumerator = new TemplateEnumerator(template);
            while (templateEnumerator.MoveNext())
            {
                if (templateEnumerator.Current.Literal.Skip == 0)
                {
                    literals.Add(templateEnumerator.Current.Literal);
                }
                else
                {
                    literals.Add(templateEnumerator.Current.Literal);
                    holes.Add(templateEnumerator.Current.Hole);
                    if (templateEnumerator.Current.Hole.Index == -1)
                        isPositional = false;
                }
            }

            Debug.Assert(holes.Count == literals.Count(x => x.Skip > 0));
            return new Template(template, isPositional, literals, holes);
        }
    }
}
